防止从 Grails 控制器写入数据库

Question

我正在编写一个小的 Grails 项目作为学习练习。它从表单收集一些用户输入（例如，输入两个数字进行相加），然后调用服务来处理该数据（例如，将两个数字相加），最后在另一个页面上显示结果。

当我打开 SQL 日志记录时，我注意到在调用控制器内的服务方法之前，用户输入的数据已保存到数据库中。

如何防止这种情况发生？我想在调用服务方法完成并且没有错误后写入数据库。

控制器代码中的保存方法：

 def save() {
      def myInstance = new myDomainClass(params)
      myInstance.sessionId = session.id
      myService argh = new myService()

      // wtf does this do?
      if (!myInstance.save(flush: true)) {
           render(view: "create", model: [myInstance: myInstance])
           return
       }

       // Execute the api and process the results. what is writing the user input to the database before this call?!?!?!?!

       def results1 = argh.executeApi(myInstance)

      // if the results are null throw an error
      if (results1 == null) {
          flash.message = message(code: 'api.null.error')
          render(view: "create", model: [apiInstance: apiInstance])
          return
      } else {
          forward(action: "list", id: 2, model: [apiInstanceList: Api.list(params), apiInstanceTotal: Api.count()])
      }
 }

感谢指点或帮助。

Answer 1

调用.save(flush:true) 会在此时自动将 myInstance 实例保存到数据库中。您需要将 .save(flush:true) 移动到服务方法之后，并且由于您说过要确保没有错误，因此您需要将其添加到条件中：

def save() {
      def myInstance = new myDomainClass(params)
      myInstance.sessionId = session.id
      myService argh = new myService()

       // Execute the api and process the results. what is writing the user input to the database before this call?!?!?!?!

       def results1 = argh.executeApi(myInstance)

      // if the results are null throw an error
      if (results1 == null) {
          flash.message = message(code: 'api.null.error')
          render(view: "create", model: [apiInstance: apiInstance])
          return
      } else {
           // save here when you know there are no errors
           if (!myInstance.save(flush: true)) {
               render(view: "create", model: [myInstance: myInstance])
               return
           }
          forward(action: "list", id: 2, model: [apiInstanceList: Api.list(params), apiInstanceTotal: Api.count()])
      }
 }

防止从 Grails 控制器写入数据库

Preventing a write to the database from Grails controller

grails